Unveiling novel threats: Urban river isolation of Aeromonas veronii with unusual VEB-28 extended-spectrum ß-lactamase and distinct mcr variants.

Aeromonas spp. are frequently encountered in aquatic environments, with Aeromonas veronii emerging as an opportunistic pathogen causing a range of diseases in both humans and animals. Recent reports have raised public health concerns due to the emergence of multidrug-resistant Aeromonas spp. This is particularly noteworthy as these species have demonstrated the ability to acquire and transmit antimicrobial resistance genes (ARGs). In this study, we report the genomic and phenotypic characteristics of the A. veronii TR112 strain, which harbors a novel variant of the Vietnamese Extended-spectrum ß-lactamase-encoding gene, blaVEB-28, and two mcr variants recovered from an urban river located in the Metropolitan Region of São Paulo, Brazil. A. veronii TR112 strain exhibited high minimum inhibitory concentrations (MICs) for ceftazidime (64 µg/mL), polymyxin (8 µg/mL), and ciprofloxacin (64 µg/mL). Furthermore, the TR112 strain demonstrated adherence to HeLa and Caco-2 cells within 3 h, cytotoxicity to HeLa cells after 24 h of interaction, and high mortality rates to the Galleria mellonella model. Genomic analysis showed that the TR112 strain belongs to ST257 and presented a range of ARGs conferring resistance to ß-lactams (blaVEB-28, blaCphA3, blaOXA-912) and polymyxins (mcr-3 and mcr-3.6). Additionally, we identified a diversity of virulence factor-encoding genes, including those encoding mannose-sensitive hemagglutinin (Msh) pilus, polar flagella, type IV pili, type II secretion system (T2SS), aerolysin (AerA), cytotoxic enterotoxin (Act), hemolysin (HlyA), hemolysin III (HlyIII), thermostable hemolysin (TH), and capsular polysaccharide (CPS). In conclusion, our findings suggest that A. veronii may serve as an environmental reservoir for ARGs and virulence factors, highlighting its importance as a potential pathogen in public health.

Efficacy and safety of antibiotics targeting Gram-negative bacteria in nosocomial pneumonia: a systematic review and Bayesian network meta-analysis.

BACKGROUND: Multiple randomized controlled studies have compared numerous antibiotic regimens, including new, recently commercialized antibiotics in the treatment of nosocomial pneumonia (NP). The objective of this Bayesian network meta-analysis (NMA) was to compare the efficacy and the safety of different antibiotic treatments for NP. METHODS: We conducted a systematic search of PubMed, Medline, Web of Science, EMBASE and the Cochrane Library databases from 2000 through 2021. The study selection included studies comparing antibiotics targeting Gram-negative bacilli in the setting of NP. The primary endpoint was 28 day mortality. Secondary outcomes were clinical cure, microbiological cure and adverse events. RESULTS: Sixteen studies encompassing 4993 patients were included in this analysis comparing 13 antibiotic regimens. The level of evidence for mortality comparisons ranged from very low to moderate. No significant difference in 28 day mortality was found among all beta-lactam regimens. Only the combination of meropenem plus aerosolized colistin was associated with a significant decrease of mortality compared to using intravenous colistin alone (OR = 0.43; 95% credible interval [0.17-0.94]), based on the results of the smallest trial included. The clinical failure rate of ceftazidime was higher than meropenem with (OR = 1.97; 95% CrI [1.19-3.45]) or without aerosolized colistin (OR = 1.40; 95% CrI [1.00-2.01]), imipemen/cilastatin/relebactam (OR = 1.74; 95% CrI [1.03-2.90]) and ceftazidime/avibactam (OR = 1.48; 95% CrI [1.02-2.20]). For microbiological cure, no substantial difference between regimens was found, but ceftolozane/tazobactam had the highest probability of being superior to comparators. In safety analyses, there was no significant difference between treatments for the occurrence of adverse events, but acute kidney failure was more common in patients receiving intravenous colistin. CONCLUSIONS: This network meta-analysis suggests that most antibiotic regimens, including new combinations and cefiderocol, have similar efficacy and safety in treating susceptible Gram-negative bacilli in NP. Further studies are necessary for NP caused by multidrug-resistant bacteria. Registration PROSPERO CRD42021226603.

Reliability of a Screening Method Using Antibiotic Disks to Detect Carbapenemases in Glucose-Nonfermenting Gram-Negative Microorganisms From Clinical Samples of a Regional Hospital in Southeastern Spain.

BACKGROUND: Infections by glucose-nonfermenting gram-negative bacilli (NFGNB) pose a major public health problem due to multiresistance to beta-lactam antibiotics, especially plasmid-borne carbapenemases. Their detection by microbiology laboratories is challenging, and there is a need for easy-to-use and reliable diagnostic techniques. Our objective was to evaluate an in-house screening method to presumptively detect carbapenemases in NFGNB in a simple and clinically useful manner. METHODS: The study included 175 NFGNB isolates from urinary, respiratory, and rectal samples. In a triple assay, isolates were incubated at 37°C for 24 h on three solid-culture media: MacConkey II Agar, 5% Sheep Blood Columbia Agar and Mueller Hinton II Agar; meropenem (MEM) and cefepime (FEP) disks were employed for screening. Studies were then performed on the inhibition halo diameter, scanning effects, and the appearance of mutant colonies, which were compared with those observed using the colorimetric Neo-Rapid CARB Kit and immunochromatography (NG5-Test Carba and K-Set for OXA-23). Receiver operating characteristic curves were constructed for these data. RESULTS: Carbapenemases were expressed by 79/175 (45.1%): 19 Pseudomonas aeruginosa and 60 Acinetobacter baumannii. Optimal inhibition halo diameter cutoffs to detect this resistance on 5% sheep blood agar were as follows: 6 mm (MEM) and 6.5 mm (FEP) for P. aeruginosa (in the absence of scanning effects and mutations) and 10.5 mm (MEM) and 16 mm (FEP) for A. baumannii (even in the presence of scanning effects). CONCLUSION: The combined utilization of MEM and FEP antibiotic disks in 5% sheep blood agar, measuring their inhibition haloes, offers an effective method to predict the presence of carbapenemases as resistance mechanism in P. aeruginosa and A. baumannii.

Antimicrobial activity of cefepime-tazobactam combination against extended spectrum beta-lactamase and/or AmpC beta-lactamase- producing gram-negative bacilli.

BACKGROUND: The problem of resistance to beta-lactam antibiotics, which is caused by ESBL and AmpC ß-lactamases, is getting worse globally. Infections caused by bacterial isolates harboring these enzymes are difficult to treat with carbapenems being the sole effective treatment option for such infections. The objective of this study was to determine the frequency of ESBLs and AmpC-producing Gram-negative bacilli isolated from clinical specimens and to evaluate the sensitivity of cefepime-tazobactam combination against them. METHODS: This is an observational cross-sectional study carried out on 100 Gram-negative bacilli at Theodor Bilharz Research Institute Hospital during the period from February 2015 to January 2016. ESBL production was screened by using the disc diffusion test followed by confirmation by the combined disc confirmatory test, the screening for AmpC production was conducted using the cefoxitin disc test, which was subsequently confirmed by the AmpC disc test. Isolates confirmed positive for ESBL and/ or AmpC production were investigated for their susceptibility to antibiotics. RESULTS: Among 100 Gram-negative bacilli, 44 isolates were confirmed as ESBL producers by the combined disc confirmatory test out of 56 isolates that tested positive for ESBL production through the disc diffusion test. The presence of AmpC production was assessed using the cefoxitin disc test, 32 isolates were screened to be AmpC producers, and the AmpC disc test confirmed AmpC production in 9 isolates of them. Using the Mast® D68C set, 32 isolates were ESBL producers, 3 were AmpC producers, and 4 isolates were ESBL/AmpC co-producers. The highest sensitivity was to cefepime-tazobactam (91.48%) followed by the carbapenems. CONCLUSION: Cefepime-tazobactam showed remarkable activity against ESBL and/or AmpC-producing Gram-negative bacilli and may be considered as a therapeutic alternative to carbapenems.

Molecular epidemiology of carbapenem-resistant gram-negative bacilli in Ecuador.

INTRODUCTION: Carbapenem-resistant gram-negative bacilli are a worldwide concern because of high morbidity and mortality rates. Additionally, the increasing prevalence of these bacteria is dangerous. To investigate the extent of antimicrobial resistance and prioritize the utility of novel drugs, we evaluated the molecular characteristics and antimicrobial susceptibility profiles of carbapenem-resistant Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii in Ecuador in 2022. METHODS: Ninety-five clinical isolates of carbapenem non-susceptible gram-negative bacilli were collected from six hospitals in Ecuador. Carbapenem resistance was confirmed with meropenem disk diffusion assays following Clinical Laboratory Standard Institute guidelines. Carbapenemase production was tested using a modified carbapenemase inactivation method. Antimicrobial susceptibility was tested with a disk diffusion assay, the Vitek 2 System, and gradient diffusion strips. Broth microdilution assays were used to assess colistin susceptibility. All the isolates were screened for the blaKPC, blaNDM, blaOXA-48, blaVIM and blaIMP genes. In addition, A. baumannii isolates were screened for the blaOXA-23, blaOXA-58 and blaOXA-24/40 genes. RESULTS: Carbapenemase production was observed in 96.84% of the isolates. The blaKPC, blaNDM and blaOXA-48 genes were detected in Enterobacterales, with blaKPC being predominant. The blaVIM gene was detected in P. aeruginosa, and blaOXA-24/40 predominated in A. baumannii. Most of the isolates showed co-resistance to aminoglycosides, fluoroquinolones, and trimethoprim/sulfamethoxazole. Both ceftazidime/avibactam and meropenem/vaborbactam were active against carbapenem-resistant gram-negative bacilli that produce serin-carbapenemases. CONCLUSION: The epidemiology of carbapenem resistance in Ecuador is dominated by carbapenemase-producing K. pneumoniae harbouring blaKPC. Extensively drug resistant (XDR) P. aeruginosa and A. baumannii were identified, and their identification revealed the urgent need to implement strategies to reduce the dissemination of these strains.

Nontuberculous mycobacteria testing and culture positivity in the United States.

BACKGROUND: Nontuberculous mycobacteria (NTM) are environmental bacteria which may cause chronic lung disease. The prevalence of NTM pulmonary infection and disease has been increasing in the United States and globally. The predominant clinically relevant species of NTM in the United States are Mycobacterium avium complex (MAC) species and Mycobacterium abscessus. With the development of rapid species identification methods for NTM (e.g. PCR probes), more testing for NTM is being conducted through commercial labs, such as Laboratory Corporation of America (Labcorp), which provides deidentified real-time testing data to the Centers for Disease Control (CDC) pursuant to a data sharing agreement. Because NTM lung infections are not reportable in most states, other data sources are key to understanding NTM testing patterns, positivity rates, and species distributions to track infection trends and identify clinical care needs. METHODS: We obtained national Labcorp data for the period January 2019 through mid-April 2022. We subset the data to only respiratory samples sent for Acid Fast Bacilli (AFB) cultures. NTM positive results were defined as those which identified an NTM species and are not Mycobacterium tuberculosis, Mycobacterium bovis, or Mycobacterium gordonae. RESULTS: Overall, 112,528 respiratory samples were sent for AFB testing during the study period; 26.3% were from the Southeast U.S., identified as HSS Region IV in the Labcorp dataset, and 23.0% were from the Pacific and South Pacific region (Region IX). The culture positive prevalence ranged from 20.2% in the Southeast to 9.2% in the East North Central region (Region V). In the Southeast US, M. abscessus prevalence was 4.0%. For MAC, the highest prevalence was observed in the Mountain region (Region VII) (13.5%) and the lowest proportion was in the East South Central region (7.3%, Region III). Among positive tests, the proportion which was MAC varied from 61.8% to 88.9% and was highest in the Northeast U.S. The proportion of positive samples which were M. abscessus ranged from 3.8% to 19.7% and was highest in the Southeast. CONCLUSIONS: The Southeastern region of the U.S. has the highest rate of culture positivity in Labcorp tests for total NTM and, of all positive tests, the highest proportion of M. abscessus. These estimates may underrepresent the true number of M. abscessus infections because M. absesscus-specific probes are not commercially available and not all NTM testing in the United States is done by Labcorp. Analysis of real-time testing data from commercial laboratories may provide insights into risk factors for NTM culture positivity in 'hotspot' areas.

Unrelenting Infection of Implanted Prosthetic Hip Joint by Corynebacterium striatum.

Non-diphtherial Corynebacterial (NDC) species, while previously considered as culture contaminants, are increasingly being implicated in clinical disease and identified as causes of opportunistic infections. In cases where they grow in pure cultures, isolated from a sterile site or repeated isolations from the same patient, NDC may be labeled as clinically significant. We report here a case of non-healing infection of one of the implanted devices in a case of bilateral total hip replacement, caused by multidrug-resistant Corynebacterium striatum. Adherence to infection prevention strategies is essential for the prevention of prosthetic implant infections.

Prediction of Tuberculosis From Lung Tissue Images of Diversity Outbred Mice Using Jump Knowledge Based Cell Graph Neural Network.

Tuberculosis (TB), primarily affecting the lungs, is caused by the bacterium Mycobacterium tuberculosis and poses a significant health risk. Detecting acid-fast bacilli (AFB) in stained samples is critical for TB diagnosis. Whole Slide (WS) Imaging allows for digitally examining these stained samples. However, current deep-learning approaches to analyzing large-sized whole slide images (WSIs) often employ patch-wise analysis, potentially missing the complex spatial patterns observed in the granuloma essential for accurate TB classification. To address this limitation, we propose an approach that models cell characteristics and interactions as a graph, capturing both cell-level information and the overall tissue micro-architecture. This method differs from the strategies in related cell graph-based works that rely on edge thresholds based on sparsity/density in cell graph construction, emphasizing a biologically informed threshold determination instead. We introduce a cell graph-based jumping knowledge neural network (CG-JKNN) that operates on the cell graphs where the edge thresholds are selected based on the length of the mycobacteria's cords and the activated macrophage nucleus's size to reflect the actual biological interactions observed in the tissue. The primary process involves training a Convolutional Neural Network (CNN) to segment AFBs and macrophage nuclei, followed by converting large (42831*41159 pixels) lung histology images into cell graphs where an activated macrophage nucleus/AFB represents each node within the graph and their interactions are denoted as edges. To enhance the interpretability of our model, we employ Integrated Gradients and Shapely Additive Explanations (SHAP). Our analysis incorporated a combination of 33 graph metrics and 20 cell morphology features. In terms of traditional machine learning models, Extreme Gradient Boosting (XGBoost) was the best performer, achieving an F1 score of 0.9813 and an Area under the Precision-Recall Curve (AUPRC) of 0.9848 on the test set. Among graph-based models, our CG-JKNN was the top performer, attaining an F1 score of 0.9549 and an AUPRC of 0.9846 on the held-out test set. The integration of graph-based and morphological features proved highly effective, with CG-JKNN and XGBoost showing promising results in classifying instances into AFB and activated macrophage nucleus. The features identified as significant by our models closely align with the criteria used by pathologists in practice, highlighting the clinical applicability of our approach. Future work will explore knowledge distillation techniques and graph-level classification into distinct TB progression categories.

Cefiderocol (Fetroja) as a Treatment for Hospital-Acquired Pneumonia.

With increasing resistance to conventional antibiotic treatments, especially among gram-negative bacilli, the search for new antibiotics has become critical on a global scale. Among infections with multidrug-resistant bacteria is hospital-acquired pneumonia (HAP), which is nosocomial pneumonia in patients who have been hospitalized for more than 48 hours. HAP carries a high mortality rate and continues to be a challenge with regard to adequate treatment. The typical multidrug-resistant gram negatives found in HAP include Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Many new antibiotics have been studied and tested against these pathogens as possible solutions, and the search continues. Cefiderocol, a novel siderophore cephalosporin, is effective against these pathogens. Cefiderocol is an iron-chelating agent that makes use of iron pumps on the membrane of bacteria via a catechol moiety on the C3 side chain of the molecule. This allows for easy access into the cytoplasm, where it can inhibit peptidoglycan synthesis by binding to penicillin-binding proteins. Cefiderocol displays linear pharmacokinetics and is mainly excreted through the kidneys. It is well tolerated in healthy individuals but may need adjustments of dosage in patients with impaired renal function. Studies have shown that both healthy subjects and those with impaired renal function experienced some adverse effects, including nausea, diarrhea, abdominal pain, and increased creatinine kinase; however, these adverse effects were limited and experienced in placebo groups. It has demonstrated efficacy in treating infections caused by many multidrug-resistant gram-negative pathogens and has demonstrated high stability against many classes of b-lactamases. There have been multiple phase 3 trials, such as the CREDIBLE-CR trial and the APEKS-NP trial, that demonstrated efficacy in treated nosocomial pneumonia caused by multidrug-resistant gram negatives, such as carbapenem-resistant Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa, compared to the best available treatment. While clinical data remain limited, a few studies are showing clinical efficacy and few adverse effects. Cefiderocol demonstrated effectivity in treating multidrug-resistant gram-negative pneumonia in patients with multiple comorbidities, such as chronic kidney disease, chronic-obstructive pulmonary disease, and diabetes mellitus. Cefiderocol shows promise as a novel antimicrobial agent in treating multidrug-resistant gram-negative in HAP.

Rapid AST: Possibility of inferring resistance mechanisms with complex phenotypes / Pruebas rápidas de sensibilidad a los antimicrobianos: ¿es posible inferir mecanismos de resistencia con fenotipos complicados?

The new automated systems designed for rapid performance of AST have significantly reduced the response time for susceptibility testing of microorganisms causing bacteremia and sepsis. The Accelerate Pheno® system (AAC) is one such system. Our objective for this study was to determine whether the AAC system is capable of providing an accurate susceptibility profile to infer resistance mechanisms in different carbapenemase-producing isolates when compared to the MicroScan WalkAway System (MWS). Disk diffusion method was also performed on all isolates as a reference method. Additionally, we compared the results obtained with the routine AST production system. We selected 19 isolates from the cryobank of the Microbiology department, all of which were carbapenemase-producing gram-negative bacilli. AAC was able to identify and infer the resistance of a total of 10 isolates, with an EA and CA of 84.2% for meropenem and 88.2% and 64.7% for ertapenem EA and CA, respectively. If we consider the disk diffusion technique, the CA was 57.9% and 76.5% for meropenem and ertapenem. However, in the presence of carbapenemases, AAC was not able to provide adequate MICs or infer the resistance mechanisms of the isolates accurately. Further studies with a larger number of isolates, including the new antibiotics ceftolozane/tazobactam and ceftazidime/avibactam, are needed for a more comprehensive comparison. (AU)

Los nuevos sistemas automatizados diseñados para la realización rápida de antibiogramas han reducido significativamente el tiempo de respuesta para las pruebas de susceptibilidad de los microorganismos causantes de bacteriemia y sepsis. El sistema Accelerate Pheno® (AAC) es uno de ellos. Nuestro objetivo para este estudio era determinar si el sistema AAC es capaz de proporcionar un perfil de sensibilidad preciso para inferir mecanismos de resistencia en diferentes aislados productores de carbapenemasas en comparación con el sistema MicroScan WalkAway (MWS). El método de disco difusión fue incluido también en todos los aislados como método de referencia. Además, comparamos los resultados obtenidos con el sistema rutinario de producción de antibiogramas rápidos. Seleccionamos 19 aislados del criobanco del departamento de Microbiología, todos ellos bacilos gramnegativos productores de carbapenemasas. AAC fue capaz de identificar e inferir la resistencia de un total de 10 aislados, con una EA y CA del 84,2% para el meropenem y del 88,2% y 64,7% para la EA y CA del ertapenem, respectivamente. Si consideramos la técnica de disco difusión, la CA fue de un 57.9% y de un 76.5% para meropenem y ertapenem. Sin embargo, en presencia de carbapenemasas, AAC no fue capaz de proporcionar CMIs adecuadas ni de inferir con precisión los mecanismos de resistencia de los aislados. Se necesitan más estudios con un mayor número de aislados incluyendo también los nuevos antibióticos ceftolozano/tazobactam y ceftazidima/avibactam para una comparación más exhaustiva. (AU)

Performance Evaluation of No-Code Artificial Intelligence Models for the Detection of Acid-Fast Bacilli: A Comparative Analysis of Three Models.

Background Acid-fast bacilli Mycobacterium tuberculosis and Mycobacterium leprae are the causative organisms behind two major diseases of developing nations, tuberculosis and leprosy, respectively. To efficiently tackle these diseases in developing nations, drugs must be augmented with improved detection modalities. This necessitates the development of enhanced tools that can aid the current detection modalities being used in high-incidence areas. A no-code artificial intelligence model based on image classification is one such tool that can be used in the identification of acid-fast bacilli. This study utilizes three such no-code artificial intelligence models that originate from three different platforms but share identical training, testing, and subsequent evaluation. Thereafter, the study is directed at comparing the three models created and identifying the one that can function as a promising support system for the detection of acid-fast bacilli. Methods To begin with, a total of 1000 images per class, i.e., positive and negative for each disease, were captured from the diagnosed slides of tuberculosis and leprosy, taken from the Department of Pathology. Subsequently, these slides were reviewed again by a pathologist to demarcate them as positive or negative for acid-fast bacilli. Once the required number of images was captured, 600 images of each class were selected as the training set, 300 images as the testing set, and the remaining 100 images as the evaluation set. Data augmentation was then performed using techniques such as rotating, mirroring, cropping, and position shifting. These designated data sets were then used to train the image classification software available on the following three platforms: Lobe (Microsoft Corporation, Redmond, Washington, United States), Create ML (Apple Inc., Cupertino, California, United States), Python-based open-source software (PerceptiLabs, Stockholm, Sweden). The final evaluation was based on different parameters such as sensitivity, specificity, ease of use, learning curve, technological resources required, and feasibility of implementation. All parameters put together served the purpose of comparison to identify the most promising model. Results Out of the three models tested, the one built using Lobe is the most promising in terms of the evaluation parameters considered. For tuberculosis, the sensitivity and specificity values obtained were 96% each, while for leprosy, they were 100% and 96%, respectively. Also, the model built using Lobe had a near-negligible learning curve, in addition to being the most cost-effective and feasible model to implement. Furthermore, it had a unique real-time training feature, which constantly improved the model throughout the testing period, till the final sensitivity and specificity values were achieved. Conclusions In clinical situations where a high number of cases are encountered each day, a no-code artificial intelligence model built using Lobe would get exposed to a huge database, getting trained in real time. Subsequently, such a model would reach considerable levels of sensitivity and specificity and in turn, act as a promising support system for the detection of acid-fast bacilli.

International guidelines for the treatment of carbapenem-resistant Gram-negative Bacilli infections: A comparison and evaluation.

OBJECTIVES: This study aimed to appraise clinical practice guidelines (CPGs) for the treatment of carbapenem-resistant Gram-negative Bacilli (CRGNB) infections and to summarise the recommendations. METHODS: A systematic search of the literature published from January 2012 to March 2023 was undertaken to identify CPGs related to CRGNB infections treatment. The methodological and reporting quality of eligible CPGs were assessed using six domains of the Appraisal of Guidelines for Research and Evaluation (AGREE) II tool and seven domains of the Reporting Items for practice Guidelines in HealThcare (RIGHT) checklist. Basic information and recommendations of included CPGs were extracted and compared. RESULTS: A total of 21 CPGs from 7953 relevant articles were included. The mean overall AGREE II score was 62.7%, and was highest for "clarity of presentation" (90.2%) and lowest for "stakeholder involvement" (44.8%). The overall reporting quality of all of the CPGs was suboptimal, with the proportion of eligible items ranging from 45.7 to 85.7%. The treatment of CRGNB infections is related to the type of pathogen, the sensitivity of antimicrobial agents, and the site of infection. In general, the recommended options mainly included novel ß-lactam/ ß-lactamase inhibitors, cefiderocol, ampicillin-sulbactam (mainly for carbapenem-resistant Acinetobacter baumannii [CRAB]), and combination therapy, involving polymyxin B/colistin, tigecycline (except for carbapenem-resistant Pseudomonas aeruginosa), aminoglycosides, carbapenems, fosfomycin, and sulbactam (mainly for CRAB). CONCLUSIONS: The methodological and reporting quality of CPGs for the treatment of CRGNB infections are generally suboptimal and need further improvement. Both monotherapy with novel drugs and combination therapy play important roles in the treatment.

Retrospective validation of MetaSystems' deep-learning-based digital microscopy platform with assistance compared to manual fluorescence microscopy for detection of mycobacteria.

This study aimed to validate Metasystems' automated acid-fast bacilli (AFB) smear microscopy scanning and deep-learning-based image analysis module (Neon Metafer) with assistance on respiratory and pleural samples, compared to conventional manual fluorescence microscopy (MM). Analytical parameters were assessed first, followed by a retrospective validation study. In all, 320 archived auramine-O-stained slides selected non-consecutively [85 originally reported as AFB-smear-positive, 235 AFB-smear-negative slides; with an overall mycobacterial culture positivity rate of 24.1% (77/320)] underwent whole-slide imaging and were analyzed by the Metafer Neon AFB Module (version 4.3.130) using a predetermined probability threshold (PT) for AFB detection of 96%. Digital slides were then examined by a trained reviewer blinded to previous AFB smear and culture results, for the final interpretation of assisted digital microscopy (a-DM). Paired results from both microscopic methods were compared to mycobacterial culture. A scanning failure rate of 10.6% (34/320) was observed, leaving 286 slides for analysis. After discrepant analysis, concordance, positive and negative agreements were 95.5% (95%CI, 92.4%-97.6%), 96.2% (95%CI, 89.2%-99.2%), and 95.2% (95%CI, 91.3%-97.7%), respectively. Using mycobacterial culture as reference standard, a-DM and MM had comparable sensitivities: 90.7% (95%CI, 81.7%-96.2%) versus 92.0% (95%CI, 83.4%-97.0%) (P-value = 1.00); while their specificities differed 91.9% (95%CI, 87.4%-95.2%) versus 95.7% (95%CI, 92.1%-98.0%), respectively (P-value = 0.03). Using a PT of 96%, MetaSystems' platform shows acceptable performance. With a national laboratory staff shortage and a local low mycobacterial infection rate, this instrument when combined with culture, can reliably triage-negative AFB-smear respiratory slides and identify positive slides requiring manual confirmation and semi-quantification. IMPORTANCE: This manuscript presents a full validation of MetaSystems' automated acid-fast bacilli (AFB) smear microscopy scanning and deep-learning-based image analysis module using a probability threshold of 96% including accuracy, precision studies, and evaluation of limit of AFB detection on respiratory samples when the technology is used with assistance. This study is complementary to the conversation started by Tomasello et al. on the use of image analysis artificial intelligence software in routine mycobacterial diagnostic activities within the context of high-throughput laboratories with low incidence of tuberculosis.

Global Resistance of Imipenem/Relebactam against Gram-Negative Bacilli: Systematic Review and Meta-Analysis.

Background: Relebactam, previously known as MK-7655, is currently being tested in combination with imipenem as a class A and class C ß-lactamase inhibitor, including KPC from Klebsiella pneumoniae. Objective: The objective of the current study was to evaluate the activity of imipenem/relebactam against gram-negative bacilli. Methods: After applying exclusion and inclusion criteria, 72 articles with full texts that describe the prevalence of imipenem/relebactam resistance were chosen for the meta-analysis and systematic review. Articles published between January 2015 and February 2023 were surveyed. The systematic literature search was conducted in PubMed, Web of Science, Google Scholar, and Scopus. Results: The pooled estimation of 282,621 sample isolates revealed that the prevalence rate of imipenem/relebactam resistance is roughly 14.6% (95% CI, 0.116%-0.182%). Conclusions: The findings of this analysis show that imipenem/relebactam resistance is rare in the majority of developed countries. Given that relebactam has proven to restore the activity of imipenem against current clinical isolates, further research into imipenem/relebactam is necessary.

An update on the prevalence of colistin and carbapenem-resistant Gram-negative bacteria in aquaculture: an emerging threat to public health.

Aquaculture has been recognized as a hotspot for the emergence and spread of antimicrobial resistance genes conferring resistance to clinically important antibiotics. This review gives insights into studies investigating the prevalence of colistin and carbapenem resistance (CCR) among Gram-negative bacilli in aquaculture. Overall, a high incidence of CCR has been reported in aquatic farms in several countries, with CCR being more prevalent among opportunistic human pathogens such as Acinetobacter nosocomialis, Shewanella algae, Photobacterium damselae, Vibrio spp., Aeromonas spp., as well as members of Enterobacteriaceae family. A high proportion of isolates in these studies exhibited wide-spectrum profiles of antimicrobial resistance, highlighting their multidrug-resistance properties (MDR). Several mobile colistin resistance genes (including, mcr-1, mcr-1.1, mcr-2, mcr-2.1, mcr-3, mcr-3.1, mcr-4.1, mcr-4.3, mcr-5.1, mcr-6.1, mcr-7.1, mcr-8.1, and mcr-10.1) and carbapenemase encoding genes (including, blaOXA-48, blaOXA-55, blaNDM, blaKPC, blaIMI, blaAIM, blaVIM, and blaIMP) have been detected in aquatic farms in different countries. The majority of these were carried on MDR Incompatibility (Inc) plasmids including IncA/C, and IncX4, which have been associated with a wide host range of different sources. Thus, there is a risk for the possible spread of resistance genes between fish, their environments, and humans. These findings highlight the need to monitor and regulate the usage of antimicrobials in aquaculture. A multisectoral and transdisciplinary (One Health) approach is urgently needed to reduce the spread of resistant bacteria and/or resistance genes originating in aquaculture and avoid their global reach.

Rapid AST: Possibility of inferring resistance mechanisms with complex phenotypes.

The new automated systems designed for rapid performance of AST have significantly reduced the response time for susceptibility testing of microorganisms causing bacteremia and sepsis. The Accelerate Pheno® system (AAC) is one such system. Our objective for this study was to determine whether the AAC system is capable of providing an accurate susceptibility profile to infer resistance mechanisms in different carbapenemase-producing isolates when compared to the MicroScan WalkAway System (MWS). Disk diffusion method was also performed on all isolates as a reference method. Additionally, we compared the results obtained with the routine AST production system. We selected 19 isolates from the cryobank of the Microbiology department, all of which were carbapenemase-producing gram-negative bacilli. AAC was able to identify and infer the resistance of a total of 10 isolates, with an EA and CA of 84.2% for meropenem and 88.2% and 64.7% for ertapenem EA and CA, respectively. If we consider the disk diffusion technique, the CA was 57.9% and 76.5% for meropenem and ertapenem. However, in the presence of carbapenemases, AAC was not able to provide adequate MICs or infer the resistance mechanisms of the isolates accurately. Further studies with a larger number of isolates, including the new antibiotics ceftolozane/tazobactam and ceftazidime/avibactam, are needed for a more comprehensive comparison.

Uncommon Location for a Common Disease, Simulating Cervical Cancer: A Rare Case Report.

BACKGROUND: Genital tuberculosis (GTB) is a common form of extra-pulmonary TB with cervical TB being a rare entity accounting for 0.1-0.65% of all TB cases globally. It is usually asymptomatic but may present with infertility, menstrual irregularities, dyspareunia, dysmenorrhoea, or vaginal discharge. CASE PRESENTATION: The present case report briefs about a 39 years old nulliparous infertile woman who presented with complaints of irregular menstrual cycles and amenorrhea with an erosive papillary growth over the cervix simulating invasive cervical carcinoma. Her Pap smear report revealed the presence of granulomas. On cervical punch biopsy also a large number of granulomas were seen and on Ziehl Nielsen staining the diagnosis of TB was further confirmed by the presence of acid-fast rodlike bacilli. The patient responded well to anti-tubercular drugs. DISCUSSION: GTB in most of the cases remains asymptomatic with infertility being the most common presenting complaint. Other symptoms include menstrual irregularities, amenorrhoea, dysmenorrhoea, dyspareunia, chronic pelvic pain, and occasionally abnormal vaginal discharge. Tuberculous cervicitis is difficult to diagnose clinically and many times mimics cervical malignancy. RESULT AND CONCLUSION: Hence, cervical tuberculosis should be kept in the differential diagnosis of cervical cancer especially in an infertile woman from a developing country.

A Randomized, Open-Label, Non-inferiority Clinical Trial Assessing 7 Versus 14 Days of Antimicrobial Therapy for Severe Multidrug-Resistant Gram-Negative Bacterial Infections: The OPTIMISE Trial Protocol.

INTRODUCTION: Shorter courses of antimicrobials have been shown to be non-inferior to longer, "traditional" duration of therapies, including for some severe healthcare-associated infections, with a few exceptions. However, evidence is lacking regarding shorter regimes against severe infections by multidrug-resistant Gram-negative bacteria (MDR-GNB), which are often caused by distinct strains and commonly treated with second-line antimicrobials. In the duratiOn of theraPy in severe infecTIons by MultIdrug-reSistant gram-nEgative bacteria (OPTIMISE) trial, we aim to assess the non-inferiority of 7-day versus 14-day antimicrobial therapy in critically ill patients with severe infections caused by MDR-GNB. METHODS: This is a randomized, multicenter, open-label, parallel controlled trial to assess the non-inferiority of 7-day versus 14-day of adequate antimicrobial therapy for intensive care unit (ICU)-acquired severe infections by MDR-GNB. Adult patients with severe infections by MDR-GNB initiated after 48 h of ICU admission are screened for eligibility. Patients are eligible if they proved to be hemodynamically stable and without fever for at least 48 h on the 7th day of adequate antimicrobial therapy. After consenting, patients are 1:1 randomized to discontinue antimicrobial therapy on the 7th (± 1) day or to continue for a total of 14th (± 1) days. PLANNED OUTCOMES: The primary outcome is treatment failure, defined as death or relapse of infection within 28 days after randomization. Non-inferiority will be achieved if the upper edge of the two-tailed 95% confidence interval of the difference between the clinical failure rate in the 7-day and the 14-day group is not higher than 10%. CONCLUSION: The OPTIMISE trial is the first randomized controlled trial specifically designed to assess the duration of antimicrobial therapy in patients with severe infections by MDR-GNB. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05210387. Registered on 27 January 2022. Seven Versus 14 Days of Antibiotic Therapy for Multidrug-resistant Gram-negative Bacilli Infections (OPTIMISE).